This disclosure relates to semiconductor memory devices, and more particularly to a semiconductor memory device including an open-bit line sense amplifier and a memory system including the semiconductor memory device.
A bit line sense amplifier of a dynamic random access memory (DRAM) senses a small difference of a signal generated on a bit line due to charge sharing between a memory cell and the bit line, and amplifies the sensed signal.
In general, the bit line of a DRAM may have an open bit-line structure or a folded bit-line structure. A DRAM having the open bit-line structure may include a bit line and a complementary bit line extending in opposite directions from a bit-line sense amplifier. In contrast, a DRAM having the folded bit-line structure may include a bit line and a complementary bit line, extending in the same direction from a bit-line sense amplifier.
Typically, a DRAM is refreshed periodically to charge/discharge a capacitor according to data stored in the DRAM.
Power consumption of a DRAM used, for example, in a mobile device is an important factor, and various efforts to reduce the power consumption have been studied. Therefore, it may help to reduce power consumption of a DRAM by reducing current consumption during a refresh operation of a DRAM.